1. Field of the Invention
Apparatuses and methods consistent with exemplary embodiments relate to a backlight unit used in a liquid crystal display, and more particularly, to a scanning backlight unit.
2. Description of the Related Art
A liquid crystal display is a display apparatus and is widely used owing to its property of reducing weight, miniaturization, full color, and high resolution. A liquid crystal panel which is used in the liquid crystal display reveals images by using a liquid crystal and a light receiving element, which is unable to emit light by itself. Accordingly, a backlight unit which supplies the light to the liquid crystal panel is required.
The backlight unit may be classified into an edge-lit backlight unit which requires a light guiding plate and a direct-lit backlight unit which does not require a light guiding plate. The edge-lit backlight unit for which the light source is mounted at one side of the light guiding plate may thin the liquid crystal display and thus is widely used recently.
In general, once a power source is applied to the liquid crystal display, the backlight unit is activated in a hold type which keeps the on-state at all times. However, if this kind of the backlight unit is used, motion blur may occur when the liquid crystal display replays the video images.
A scanning backlight technique has been disclosed as one of the methods to prevent motion blur, and the backlight unit which is applied to the scanning backlight technique is calls as a scanning backlight unit. In the scanning backlight technique, the backlight unit is divided into plural sections and each section repeats an on state (i.e., a state of supplying the light to the liquid crystal panel) and an off state (i.e., a state of not supplying the light to the liquid crystal panel) consecutively. For example, in a certain time, the first section of the backlight unit may be in an on state and the remaining sections of the backlight unit may be in an off state and, in the next time, the second section of the backlight unit may be in an on state and the remaining sections of the backlight may be in an off state. By the consecution of this process, the motion blur may be prevented.
If the first section of the backlight unit is in an on state, it is preferable that only the first section of the backlight unit supplies the light to the liquid crystal panel and the remaining sections of the backlight unit should not supply the light to the liquid crystal panel. However, in the edge-lit backlight unit where a light guiding plate is used, the light in the first section of the backlight unit is spread to the other section of the backlight unit due to the dispersion phenomenon in the light guiding plate. Accordingly, the other section of the backlight unit partially supplies the light to the liquid crystal panel. In this case, crosstalk may occur on the images which are reproduced by the liquid crystal display. Therefore, a technique which may prevent such crosstalk is needed.